Train-control system



Dec. 2,y 1930.

T. BODDE TRAIN CONTROL SYSTEM Filed OCT.. 30, 1926 2 Sheets-Sheet l ma?@M11/vento?,

attorney,

Dec. 2, 1930. T. BODDE 1,783,491

. TRAIN CONTROL SYSTEM Filed oct. so, 192e 2 sheets-sheet 2 PatentedDec. 2, 1930 UNITED star-sis PATENT ofi-*eres '.rnaononn Bonne, orNiAGARA FALLS, NEW Yo'RK, AssI'GNoR. 'ro THE REGANSAFETY nnvronscompartir, inc., or NnWYoR-K, N. Y., ACORPORATIONJOF NEWYORK'TRAIN-CONTROL sYsrEM Applicationfled October 30, 1926. Serial No.`-1`45,1'91.

This invention relates broadly to railway signalling and train controlsystems. More particularly, the present invention-is directed to railwayinduction signalling and control systems.

Thepresent invention constitutes `an imn provement on the systemdisclosed and claimed in Patent No. 1,521,332 to A. Gr. Shaver. Thispatent discloses an induction io signalling and control system, in whicha train carried device comprising two induc A tively coupled elements,one of which constitutes aprimary and the other ya secondary, cooperatewith the roadside inductor. l5 The. roadside inductor comprises a bodyof magnetic material disposed inthe path of travel of a passing train insuch a'manner that the primary of the train carried 'devices will passimmediately over the roadside device. rlhe roadside inductor is,finally, provided with a winding and with circuit means whereby saidwinding may be open circuited or short circuited depending upon thetraiiic condition of the immediateblock.

It is the object of the present invention to improve Idie operatingcharacteristics of the system and to obviateV any possibilityofobtaining an erroneous indication. i

The invention will be more clearly understood by reference to theaccompanying vdrawing and a description thereof.

In 'trie drawings,

Figure 1 is a diagrammatic illustration of the basic elements of thesystem embodying the present invention;

:Figure 2 is a showing 01": the roadside inductor embodying the presentinvention;

Figure 3 shows the operating'characteristics of the system with andwithout the present improvement; f

Figures 4 and 5 are diagrammatic showings of the theory of operation ofthe system embodying the present improvement.

Referring to Figure 1, 10isa source of alternating current and 11 and-12 constitute the primary and secondary;respectively of the-traincarried device which is adapted to cooperate with the roadside inductor513 to pick up the indication of the traffic conditi-on of the:immediate block. The train also car Frente. `tem, therefore, is that'when the train'fcarricd ries la .twopart rel-ay comprising the element14 Which is permanently connected to the source 1() and thefrotatableelement which is connected to the winding 16 of the train carriedsecondary 12. The winding 17 of the.

train carried, primary is also connected tothe source of current 10. Theroadsideinductor is provided with a Winding 18. A condenser. 19 isconnected in series with the winding and the circuit ofthe winding maybe closed Vinthe patent referred to above is vas follows;

The inductors 11 and 12 are carried by the train and are so disposedthat the inductor 11 passes directly over the roadside in ductor 1-3.It' the Winding of the roadside inductor 13 lis-open circuited theelectromagnetic relationships of the train carried elements will bedisturbed-and the trip controlrelay 15 `will operate to 4open thecontacts 23, 24 and` thereby eect' an application 'of the brakes or giveany other desired indication. It, however, the circuit of' the Winding18 of the roadside inductor is closed fat the time the train passesthereover, the lelectromagnetic relationships will not'be disturbed andthe train carried vsystem will remain unaffected.

Theelements lll and 15 ofthe trip relay are both normally energized, and`under normal `conditions,fthe element liexertsa torque `upon theelement 15 'so that the contacts 23,

24 are maintainedclosed. This torque is the result oi ,the fattractiveforces that exist between the currents lcarried by these elements and,the sizeof the torque is influenced by the amc-unt of current in each ofthe elements and by the phase relationship between suchfcur- One view ofthe voperaion ofthe sys- `devices pass `over',the-'roadsitle inductorhaving its winding open circuited, the torque between the elements 14and 15 will be dimin` ished to such an extent that the element 15 willrotate and open the contacts 23, 24:. It has been commonly assumedhitherto that when the train carried devices pass over a short circuitedroadside inductor the torque between the elements 14 and 15 does notsubstantially diminish. Bileasurements of the torque, however, haveshown that while there is no substantial diminution of the torque overthe greater part of the time it takes the train carried inductor to passover the roadside inductor, there is a substantial diminution of thetorque at the time when the train carried inductor first enters a spaceoverlying the roadside inductor. Figure 3 of the drawings is a graphicillustration of the torque measurements obtained under such conditions.The curve a-b-c-d-e which includes the dotted portions shows the mansner in which the torque varies as the train carried inductor passes overthe roadside inductor.

It is the object of the present invention to modify the system in such amanner as to obviate the dips shown by the dotted portions of the curveand to prevent any substantial reduction of the torque when the roadsideinductor' is short circuited. This object is accomplished in the presentinvention by pro` viding` a roadside inductor with one addi tionalwinding at each end which will be hereinafter referred to as shadingcoils. Those coils are indicated by the reference numerals 25 and 26.They are wound in opposition to each other and are short circuited oneach other. TvVhen the roadside inductor is provided with shading coilsthe curve a-f--g-e. which is obtained, it will be seen, practicallyeliminates the dips in the curve which exist when the old type ofroadside i nductor is used.

In order to facilitate the understanding of the principle underlying thepresent invention a theory of operation of the entire system issubmitted herewith.

Normally, that is, at such times when there is no roadside inductor inproximity with the train carried inductors, inductors 11 and 12constitute a primary and a secondary respectively of a transformer. Thecores of these two inductors are separated by air gaps. A fiux generatedin the inductor 11, therefore, has two external paths. One of thesepaths leads through the core of the secondary 1Q and the other leadsthrough the surrounding` air. The flux in the primary 11 is determinedby the electromotive force impressed upon its winding and is constantregardless of the reluctance of the magnetic circuit outside the element11.

A certain definite magnetomotive force is consumed in the core of theelement 11. The other part of the magnetomotive force is spent inpassing the linx through the two external paths described above. In viewof the fact that the flux within the core of the element 11 remainsconstant, and in View of the fact that the reluctance of that coreremains constant, the portion of the magnetomotive force that is spentin this part of the magnetic circuit remains constant. The magnetomotiveforce that is spent on the external circuit is applied to two parallelmagnetic paths, one path being entirely through the air and the otherpath being through the air gaps that exist between the elements 11 and12 and through the core of the element 12.

W'e will now introduce the roadside inductor 13 and for the first case,we will assume that its winding is open. Conditions are as follows:

Inasmueh as the voltage applied to the element 11 is constant, the fluxpassing through the element is the same. The reluctance of the externalmagnetic circuit is lowered by reason of the introduction of theroadside inductor 13. The reluctance of the path which includes the coreof the element 12 is the same. The total reluctance of the magneticpaths external to the element 11 has, therefore, been decreased and themagnetomotive force required to set up the flux in these externalcircuits has decreased which in turn results in a decrease of the fiuxwhich passes through the core of the inductor 12. The effect of thisreduction in flux through the element 12 is to decrease the voltage andcurrent in the circuit which includes the trip rela-y 15. 4

7e will next assume that the roadside inductor has been wound and shortcireuited but we will assume that the condenser 19 is not included inthe circuit. It is to be noted at this point that the train carriedinductors are a good deal shorter than the roadside inductor and areapproximately one-third the length of the roadside inductor. In View ofthis fact, the train carried inductor overlies only that part of theroadside inductor which lies directly below the train carried inductorand which constitutes a secondary with relation to the element 11, whilethe remainder of the roadside inductor merely constitutes the highlyinductive load on the secondary. When the train carried inductoroverlies approximately the middle portion of the roadside inductor, thismiddle portion constitutes an induced secondary while the end portionsconstitute a load upon the secondary. A current will flow in the winding18 of the roadside inductor which will set up afluxin opposition to thefiux set up at the primary 11. The current taken by the element 11 willincrease by an amount sufficient to set up an additional flux equal andopposite to that set up by the roadside inductor so that the resulta-ntflux set up by the element 11 is the same as that previously considered.Were there no other factors considered,ztheflux passing through theelement 112 would lb'ethe same as whenvthe roadside inductor was in opencircuit. At this point, however, magnetic leakage comes into play. `Asis wellr known, when the secondary of a transformer is loaded a leakageflux is produced bothby the primary and secondary which in ordinaryltransformers takes a leakage path partly through the air.v In a.transformer of the `kind under consideration where there are largeairgaps between the iron cores and also because of the presence of the lowreluctance path through the element 12, the leakage fluxwill beconsiderable. The primary leakage flux will'- be in phase with the totalprimary current while the secondary leakage'liux will be in phase withthe secondary current. Part'of this leakage flux will take `a paththrough the element 12, thus increasing the flux in this element. Thiswill serve to increase the voltage introduced in the winding of theelement 12 and thereby increase the current in the relay 15. Further7since the inductance of the external circuit tor the roadside inductoris much greater than for the element 12, theleakage flux will not be inphase with the regular flux in the element 10 so that the resultantcurrent in 12 will not be due to the arithmetical sum o't the Atwofluxes.` It must be remembered that the trip relay is a two elementrelay and when the 'resultant current in 1.5 isin a diiie'rent phasefrom the current previously 'lowing, `the proper phase relationbetweenthe two elements ot' the relay will be disturbed and Ythe torquewill be .reduced. i

' Vle now introduce the condenser 19 in the circuit of the roadsideinductor. This condenser has two effects.A YThe `first effect is toincrease the currentilow in the winding .of the roadside inductor due tothe reduction in the impedance of its circuit. This increased currentwill increase the leakage luX previ? ously referred to. The condenserwill also have the effector' changing the phase ot the current iowing inthe circuit of the roadside inductor so as to produce a leakage iiuXwhich will be more nearly in phase with the' regular ilus' passingthrough the element 12. ldor .maximum results, the condenser should beot such valueas to bring the leakageftlux and the regular tluX in theelement 12 exactly in phase. The result now obtained is to.in crease`the flux in the element 12, the total linx now being equal to the fluxwhich passed through the element 12 under the lirst conditions assumedplus'the Vleakage flux. vThis increases the'volta'ge induced in 'thewinding of the element 12 and increases. the current llowing inthe triprelayl, and'inaintainsthis current at substantially the same level asunder normal conditions. The phase of this current remains the sameasunder normal conditions. Under such conditions, therefore, the ltorcl-uebetween'l lthe elements 14 and 15 will increase.

The abovel discussion' explains the tulzl line portionv of the curve inFigure '3. le shall now proceed with an explanation of the dotted lineportions b and CZ of the curve. The portion of the torque curve arisesat the time when the clement 11 is coming into correspondence with theroadside indu'ctor. Under such conditions only a small end portion ofthe winding 18 constitutes a secondary of the transformer while all ofthe remaining portion of the winding constitutes-a load upon thatsecondary. Comparing these conditions with the conditions discussedherein above, when the train carried inductor'oyerlies substantially themiddle portion of the roadside inductor, thesecondary winding generatesa considerably smaller voltage and the load upon this secondary isconsiderably greaterv than under the conditions lirst discussed. Figure4l illustrates diagram matically the conditions that exist when thetrain carried inductor overlies substantially the middle portion of theroadside inductor while Figure 5 illustrates diagrammatically theconditions that exist when the train Carried inductor overliesl one sideof the roadside inductor.

ln Figures l Aand 5 the primary inductor is represented at a certain"moment'when it has a polarity N-S as shown. ln both cases the polaritywill induce in the roadside inductor winding a current which willproduce poles opposite to the prima-ry train inductor. ln the absence ofthe auxiliary or shading coils 25, 26 the poles induced on the roadsideinductor when the parts are as shown in Figure 5 will be very weak ascompared with the strength of the poles induced on the roadside inductorwhen the parts are as shown in Figure la The reason for this dilierencein strength lies in the tact that the load upon the secondary underconditions shown in Figure 4l consists of two coils, one on each side ofthe secondary, each having halt' the number or turns or the onecontinuous coil which constitutes the load upon the secondary underconditions shown in Figure 5. The inductance of a coil varies'approximately with the square of the number of turns in the coil.

For this reason, the inductance Aof the load coil under conditions'shownin Figure 5 is about twice as great as the inductance oit the two coilswhich constitute the load on the secondary under conditions shown inFigure el. The air gaps shown in Figures 4 and 5 between the variousparts of the roadside inductor are only for the purpose of thediagrammatic illustration and do not actually .exist in the device asconstructed and used.

The Vcondenser having been adjusted for maximum eiect under thecondition when the train carried inductor overlies themid- Cil CTI

dle portion of the roadside inductor, it fails to have the same effectfor the condition when the train carried inductor overlies an endportion of the roadside inductor. In the absence, therefore, or' anycompensating means such as the shading coils which constitute thepresent improvement, a substantial decrease in the iiux in the element12 would be produced as pre 7iously explained. This decrease would beonly partially compensated by the leakage iux, which leakage flux wouldnot be ot the proper phase. Due to these facts, therefore, the currentcarried by the relay is substantially reduced at the time when the traincarried inductors enter into correspondence with the roadside inductorand also at the time when they leave such correspondence. During suchoperations of the passage ot the train carried inductor over theroadside inductor, therefore, the torque between the elements 11i and 15is substantially reduced as shown by the dotted portions Z) and e of thetorque curve in Figure 3.

The shading coils and 26 are introduced in order to compensate for theundesirable elitects indicated above. These coils consist of but a fewturns so that their inductance is very low. As the train carriedinductor 11 comes into correspondence with the roadside inductor 13 alarge current will be induced in the shading coil 25 which will set upa. leal;- age iiux of approximately the proper phase and cause anincreased flux to pass through the element 12. The same phenomenon willtake place when the train carried inductor leaves the roadside inductor,The two coils 25 and 26 are so interconnected that when the traincarried inducto` is in a position overlying substantially7 the middleportion of the roadside inductor, the induced currents in the coils 25and 26 will oppose and neutralize each other so that they will beineifective.

From the above it will be seen that the condenser 19 serves the doubletunction of reducin g the total impedance of the roadside inductorcircuit and to bring about the proper phase relationship between thecurrents in the elements 14 and 15 of the trip relay, when the traincarried inductor overlies substantially the middle portion ot theroadside inductor. Under such conditions the shading coils 25 and 26oppose each other and serve no function. lVhen, however, the traincarried inductor overlies an end portion ot the roadside inductor, theshading coils 'function in a manner to increase the leakage flux in theprimary train carried inductor 1l thereby increasing the flux passingthrough the secondary train carried inductor,' 12, which in its turnbrings about an increase in the current in the tripping element 15.Moreover, the shading coils also serve to bring the current in thetripping element 15 into proper phase relationship with the current inthe tripping element 14.

Having described the invention, it is not to be limited to the speciiicembodiment shown in the specification and drawings.

`Vhat is claimed is:

1. A roadside tripping apparatus for an induction train control systemcomprising an element or' magnetic material, a winding on said element,a circuit devoid of an energy source for said winding, means for openingand closing said circuit, and an auxiliary compensating or shadingwinding on an end of said element.

2. A roadside apparatus for an induction train control system comprisingan element of magnetic material, a winding on said element, a circuitfor said winding, means for opening and closing said circuit, andoppositely wound auxiliary compensating or shading windings on the endsof said element.

3. A roadside apparatus for an induction train control system comprisingan element oi" magnetic material, a winding on said element, a circuitfor said winding, means for opening and closing said circuit, andoppositely wound auxiliary compensating or shading windings on the endsof said element, .said shading windings having a low inductance.

Ll. In an induction train control system, the combination of Vehiclecarried apparatus comprising inductivcly coupled coils, roadsideapparatus comprising an inductor embodying a circuit Operable inaccordance with wayside conditions for magnetically shunting the vehiclecarried apparatus when said circuit is open and Jfor permitting anuninterrupted operation of said vehicle carried apparatus when saidcircuit is closed and mea-ns cooperating with said roadside apparatus toprevent any substantial magnetic shunting when said circuit is closed.

5. ln an induction train control system, the combination of vehiclecarried apparatus comprising inductively coupled coils and a roadsideapparatus comprising an induction element for producing an indication insaid vehicle carried coupled coils, circuit means associated with saidelement for producing another indication in said vehicle carried coupledcoils and means associated with said element for supplementing theoperation of said circuit and aiding in the production of the otherindication.

G. ln an induction train control system, the combination of vehiclecarried apparatus comprising inductively coupled coils and a roadsideapparatus comprising an induction element tor producing a dangerindication in said vehicle carried coupled coils, circuit meansassociated with said element for producing a clear indication in saidvehicle carried coupled coils and means associated with said element forsupplementing the operation of said circuit and aiding in the productionof the clear indication.

Sli

7. In an induction train control system, the combination of vehicle`carried apparatus comprisinginductively coupled coils and a roadsideapparatus comprisingan element of magnetic material, a winding on-saidelement, a circuit for said winding, means whereby said circuit may beopened to produce danger indication in :said inductivelycoupled coilsand closed to Vproduce a clear indication and means on said elementineii'ective when said circuit is open and :effective for supplementingthe operation of said circuit and to aid lin #the production of theclear indication when said circuit is closed.

8. In an induction train control system, the combination of vehiclecarried apparatus comprising inductively coupled coils and a roadsideapparatus comprisinganelement of magnetic material cooperating directlywith said inductively coupledcoils, a winding on said element, a.circuit devoid of an `energy source for said winding, means for openingand closing said circuit, and auxiliary shading windings on saidelement.

9. In an induction train control system, the combination of ilehiclecarried apparatus comprising inductively coupled coils and a roadsideapparatus comprising an. element of magnetic material cooperatingdirectly with said inductively coupled coils, a winding on said element,a circuit Vdevoid of an energy source orsaid winding, means for openingand closingrr said circuit, and VauX- iliary shading windings lon theends of said element.

10. In an induction train control system, the combinationof vehiclecarried apparatus comprising inductively coupled coils and a roadsideapparatus comprising an element of magnetic material, a `winding on said.element, a circuit for said winding, means for opening and closing saidcircuit, and oppositely wound auxiliary shading windings lon the endsofsaid element. i

11. In an induction train control system, the combination of vehicleVcarried apparatus comprising inductivelycoupled coils and a roadsideapparatuscomprising an element of magnetic material, a winding on said.element, a circuit for said winding, means for opening and closing saidcircuit, and oppositely wound `auxiliary shading windings on the endsofsaid element, said shading windings having a low inductance. 1

12. Aninduction train control system, the combination of vehicle carriedapparatus comprising a pair of inductively coupled coils, a source ofenergy connected to one of said coils and a relay connected to the otherof said coils, and roadside apparatus inductively cooperating with saidvehicle carried apparatus comprising an inductor embodying a circuitoperable in accordance with wayside conditions lto reduce the current insaid relay when the circuit is open and to maintain ,the current inVsaid relay when the circuit 'is' closed and means `cooperating withsaid roadside apparatus `aiding in Vthe maintainance of the current insaid relay.

18,. `In an induction train control system,

`the combination oi' vehicle carried apparatus comprising a coil, asource oi energy `connected to said coil, a second coil inductivelycoupled to said first coil, `and `roadside Vap paratus indiictivelycooperating with said' vehicle carried apparatus comprising a rela-'.t-ive'ly 'long element of magnetic material having an entrant end andan exit end, a winding on said-element, a circuit for said windingoperable in accordance with roadside conditions'fcr reducing the flux insaid second coil when said circuit is open, and means cooperating with`said element and said winding for maintaining the flux in said secondcoil when 'the circuit is closed. Y

141. 'In an induction train control Vsystem the combination of Vehiclecarried apparatus comprising `a coil, a source of energy connectedtosaid coil, -a `second coi'linductively coupled to said first coil, androadside apparatus inductively `cooperating with said vehicle carriedapparatus comprising a relatively long element-,of magnetic materialhaving an entrantenld and an `entend, a winding onsaid element, acircuit for said winding operable in accordance with `roadsideconditions for reducing the vflux in said second coil when .said circuitis open, and means on said elementCOQPSlilIl-g with, said element andsaidvwinding for maintaining the linx in said second coil when thecircuit is closed;

15. In an induction train controlV system, thel combination -of vehiclecarried apparatus comprising a coil, a source of energy connectedto saidcoil, a seccnd coilinductively coupled to said iirst coil, and roads-ideapparatus inductivelycooperating with said yehicle carried apparatuscomprising a relatively long element of magnetic material having anentrant end andan exit end, a winding on said element, a circuit forsaid winding 4operable in accordance with roadside conditions forreducing the flux in said second `coil when said iis circuit 'is open,,and auxiliary windings cooperating with said element and said windingfor maintaining the flux in said'second Coil when the circuit isclosed'.A f

1,6. Inail induction train control system,

the combination ci vehicle carried apparatus.

reducing the luX in said second coil when said circuit is open, andauxiliary windings on the ends of said element cooperating with saidelement and said winding for maintaining the liux in said second coilwhen the circuit is closed.

17. In an induction train control system, the combination otl vehiclecarried apparatus comprising a coil, a source of energy connected tosaid coil, a second coil inductively coupled to said iirst coil, androadside apparatus inductively cooperating with said vehicle carriedapparatus comprising a relatively long element ot magnetic materialhaving an entrant end and an exit end, a winding` on said element, acircuit for said winding operable in accordance with roadside conditionsfor reducing the liuX in said second coil when said circuit is open, andoppositely wound auxiliary windings cooperating with said element andsaid winding for maintaining the flux in said second coil when thecircuit is closed.

18. In an induction train control system, the combination of vehiclecarried apparatus comprising a pair of inductively coupled coils, asource of energy connected to one of said coils, a two element relayhaving one of its elements connected to said source of energy and havingthe other of its elements connected to the other of said coils whereby aconstant torque is exerted by one element upon the other, roadsideapparatus inductively cooperating with said vehicle carried apparatuscomprising a relatively long` body of' magnetic material, a windingonsaid body, a circuit for said winding, means operable in accordancewith roadside conditions for opening and-closing said circuit and meanscooperating with said winding when its circuit is closed whereby thetorque upon said element is maintained substantially constant.

19. In an induction train control system, the combination of vehiclecarried apparatus comprising a. pair of inductively coupled coils, asource of energy connected to one of said coils, a two element relayhaving one of its elements connected to said source of energy andhaving` the other of its elements connected to the other of said coilswhereby a constant torque is exerted by one element upon the other,roadside apparatus inductively cooperatingv with said vehicle carriedapparatus comprising a relatively long body of magnetic material, awinding on said body, a circuit for said winding, means operable inaccordance with Vroadside conditions for opening and closing saidcircuit and means disposed on the ends of said body cooperating with thewinding on said body for maintaining` said -torque substantiallyconstant when the circuit of said winding is closed.

20. In anl induction train control system, the combination of vehiclecarried apparatus comprising a pair of i-nductively coupled coils, asource of energy connected to one of said coils, a two element relayhaving one of its elements connected to said source of energy and havingthe other' of its elements connected to the other of said coils wherebya constant torque is exerted by one element upon the other, roadsideapparatus inductively cooperating with said vehicle carried apparatuscomprising a relatively long body oi magnetic material, a winding onsaid body, a circuit tor said winding, means operable in accordance withroadside conditions for opening and closing said circuit and means onsaid body cooperating with the winding when its circuit is closed tomaintain the magnitudes and phase relationships of the currents in saidelements sul'istan'tially in their normal condition.

21. In an induction train control system, the combination of vehiclecarried apparatus comprising a pair of inductively coupled coils, alsource o'fenergy connected to one of said coils, relay connected to theother ot' said coils, a roadside inductor cooperating with said vehiclecarried apparatus comprising a relatively long body of' magneticniaterial, a winding on said body, a circuit for said winding, means foropening and closing said circuit in accordance with roadside conditionsand means for preventing any substantialreduction of the torque of saidrelay when the vehicle carried coils overlie the entrant or the exitends of the roadside inductor.

22. In an induction train control system, the combination of' vehiclecarried apparatus comprising a pair of inductively coupled coils, asource of energy connected toone ot said coils, a relay connected to theother o? said coils, a roadside inductor cooperating with said vehiclelcarried apparatus comprisa relatively long body of magnetic material, awinding on said body, lircuit tor said winding, means for opening andvclosi n g said circuit in accordance with r adside conditions andoppositely wound auxiliary coils on the ends of said body cooperatingwith the winding when its circuit is closed to prevent any substantialreduction in the torque oic the relay when the vehicle carried inductorsoverlie the entrant or exit ends oit the roadseue inductor. Y

Signed at Niagara Falls in the county of Niagara and State of N ew Yorkthis 7th day of October, A. D. 1926.y

THEODORE BODDE.

